Method for trimming edges of sheets



y 1965 R. T. MERCER ETAL 3,185,006

METHOD FOR TRIMMING EDGES OF SHEETS Original Filed June 18, 1962 5 Sheets-Sheet l INVENTORS. 5?

A TTORNEYS.

y 25, 1965 R. T. MERCER ETAL 3,185,006

METHOD FOR TRIMMING EDGES OF SHEETS Original Filed June 18, 1962 5 Sheets-Sheet 2 y 1965 R. T. MERCER ETAL 3,185,006

METHOD FOR TRIMMING EDGES OF SHEETS Original Filed June 18, 1962 5 Sheets-Sheet 5 ID' 61mm 9 [I /NVEN7'ORS.'

ATTORNEVYS.

y 25, 1965 R. T. MERCER ETAL 3,185,006

METHOD FOR TRIMMING EDGES OF SHEETS Original Filed June 18, 1962 5 Sheets-Sheet 4 ATTORNEYS.

May 25, 1965 R. 1'. MERCER ETAL METHOD FOR TRIMMING EDGES OF SHEETS 5 Sheets-Sheet 5 Original Filed June 18, 1962 INVENTORS: gimzjmaw W% @Zz0,

ATTORNEYS.

ll'lllllllJ United States Patent 3,185,006 METHOD FOR TRIMMING EDGES (BF SHEETS Robert I. Mercer, Lima, Ohio, Laurence W. Secrest, Alexandria, Va, and Frank J. Zsebo, Silver Spring, Md, assignors to Lennox Industries, Inc., Marshalitown,

Iowa, a corporation of Iowa Original application June 18, 1962, Ser. No. 203,178, now Patent No. 3,153,962, dated Oct. 27, 1964. Divided and this application Nov. 12, 1963, Ser. No. 322,706

3 Claims. (Cl. 83-33) This invention relates in general to a method for trimming the side edges of sheets of metal or the like so that they are parallel to each other and bear a desired angular relation to an end edge of the sheet, the present application being a division of our copending application, Serial No. 203,178, filed June 18, 1962, and now Patent No. 3,153,962.

Sheet metal as rolled at the mill does not have truly parallel straight side edges but rather somewhat wavy side edges which are in general parallel but not straight. An attempt to trim the edges parallel and straight by passing them through spaced apart shearing rollers and, then cutting lengths from .the ribbon of sheet metal is not successful in producing truly straight and parallel sides with end cuts at a desired angle (usually 90) to the side edges of the sheet.

Accordingly, one object of our invention is to provide a method wherein first of all rough lengths are cut from the ribbon of sheet metal, and then the two side edges are trimmed accurately at the desired angle with relation to a front edge of the sheet and parallel to each other whereby a sheet having three straight edges results with the side edges parallel. The sheet may then be trimmed to length at the rear edge and at the desired angle relative to the parallel side edges.

Another object is to provide a method for trimming edges of a sheet comprising the steps of cutting a length of sheet from a ribbon of sheet, moving the length of sheet longitudinally to engage its leading edge with a pair of spaced stops to orient said leading edge, gripping the oriented sheet, moving it as oriented longitudinally, and trimming the side edges of the sheet at a predetermined angle relative to the oriented leading edge thereof.

As coiled steel strip is rolled at'the mill there is what is commonly called camber rolled into almost any strip. Camber is defined as the lateral curvature or deviation from an imaginary Straight line if the coil were unrolled and laid out flat. This deviation can be as much as one inch in twenty feet of strip length.

In the conventional edge trimming system as done in a continuous strip limit is impossible to remove all the camber from a strip as the cutterstend tofollow the existing camber, even when a tracking or edge sensing device to control the path of the edge of the strip is used. The strip therefore cannot be cut into finished square sheets.

Accordingly, it is our purpose to provide a method that produces a sheet with both sides straight, parallel and square or at some desired angle other than 90 with the leading edge. This is accomplished by edge trimming both sides of the sheet after it has been cut from the coil. By doing this we eliminate the camber from the coil. Since the sheet is now no longer a part of the coil we can trim the edges square with the leading edge because we register the leading edge against stops, clamp it and then drive it between the cutters while maintaining this oriented position. The only succeeding operation necessary to obtain a perfectly square sheet to desireddimensions is to reshear the trailing edge to the required length and square with the side edges.

. This last shearing operation is only necessary where camber in the coil is severe enough to cause the leading edge of the sheet to be out of parallel with the trailing edge. In other words, if the strip moves from side to side as it traverses through the decoiling and shearing line the shear cuts will not be parallel and will require reshearing of the trailing edge. Since this is the rule rather than the exception however we initially cut the sheets slightly longer than necessary and the last shearing operation is then performed to cut them to the exact lengths desired.

With these and other objects in view, our invention consists in the steps of our method the construction, arrangement and combination of the various parts of our apparatus for trimming edges of sheets, whereby the objects above contemplated are attained, as hereinafter more fully set forth, pointed out in our claims and illustrated in detail on the accompanying drawings, wherein:

FIG. 1 is a front elevation of our apparatus as claimed in the above copending application for practicing our method for trimming edges of sheets.

FIG. 2 is a plan view thereof.

FIG. 3 is an end elevation looking at the right hand end of FIG. 1.

FIG. 4 is a diagrammatic perspective View thereof.

FIGS. 5, 6, 7, 8 and 9 are diagrammatic views showing the position of various parts and various automatic operations that occur during a cycle of operation of our apparatus.

FIG. 10 is an enlarged vertical sectional view on the line 10-10 of FIG. 2 showing a sheet stop and cutter knives, limit switches in relation thereto.

FIG. 11 is an elevation of one of the limit switches shown in FIG. 10 as on the indicated line 11- 11 thereof.

:FIG. 12 is a sectional view similar to a portion of FIG. 10 but taken at a different plane for showing further details of the stop, and

'FIG. 13 is a plan view of the stop.

On the accompanying drawings we have used the reference numeral 14 to indicate a base housing on which the elements of our apparatus are mounted. Adjustable feet 16 serve to support the base 14 and level it with relation to a floor surface indicated at 15 in FIG. 1.

Bearing standards 18, 20, 22 and 24 are mounted adjacent four corners of the base housing 14 and in their upper ends are provided with bearings for supporting pinch rolls PR1 and PR2 on the standards 18 and 20 and PR3 and PR4 on the standards 22 and 24 in such manner that the rolls PR1 and PR3 are fixed in elevation relative thereto and the rolls PR2 and PR4 may be lowered in to contact with the rolls PR1 and PR2 or raised out of contact therewith by means of two pairs of double acting pneumatic cylinders C3 and C4 for the pinch roll PR2 and a second pair C5 and C6 for the pinch roll PR4.

The pinch rolls are adapted to be driven from a drive shaft 26 through a clutch CL the output of which comprises a shaft 27 operatively connected by means of chains 28 and 30 directly to the pinch rolls PR1 and PR3. A pair of intermeshing gears 32 is provided for driving the pinch roll PR2 from the pinch roll PR1 and a similar pair for driving the pinch roll PR4 from the pinch roll PR3, each pair including a universally jointed jack shaft 34 shown in FIG. 1 to permit the raising and lowering of the rolls PR2 and PR4 by means of the cylinders C3, C4, C5 and C6 yet maintain proper driving connection.

Horizontally between the entrance pinch rolls and the exit pinch rolls, four freely rotatable; rollers 36 are provided extending substantially the full length of the pinch rolls, and eight of them indicated 38 or shorter length extending between the rollers 36 as shown in FIG. 2. The rollers 38 are rotatably supported by the flanges of a channel shaped member 39.

Longitudinally of the base housing 14 are a pair of ways 40 and 42 shown in FIG. 3. A pair of cutter carryable transmission mechanism within the housings 44 and i 46 from a splined drive shaft 56 extending through both of the housing 44 and 46 and through a transmission housing 58 shown in FIG. 1 wherein means is provided for driving the'shaft 56 from the shaft 26. The splined portions of the shaft 56 are protected by a pair of bellows 60, the right hand one in FIG. 1 being broken away to show the shafti56 therein is driven by suitable mechanism in a transmission housing'64 from an electric motor or other suitable prime mover indicated at 66.

For adjusting the housings 44 and 46 longitudinally of the ways 40 and 42 hand wheels 68 and 70 are provided secured to threaded rods 72 and 74 coaoting with depending brackets 75 and 77 from the housing as also shown in FIG. 1. Thus the distance apart of the cutting edges of the rotarycutter knives C1 and C2'may be adjusted as from the maximum shown by solid lines in FIG..1 to a minimum shown by dot-and-dash lines, and thedevice is thereby adjusted for trimming the'side edges of sheets to. various Widths.

Referring to FIG. 2 an arrow 76 shows the direction that the sheet of metal passes through the apparatus. Be-.

fore reaching the cutter knives C1 and C2 the sheet'engages stops S which are shown in detail in FIGS. 10, 12 and 13. frame of the machine and connected electrically with a wire 78. As shown in FIG. 4 there are two of the wires,

whileFIG. 6 indicates these wires extending to a sensing 7 device SDand an amplifier A. The sensing device reof metal bridges the two stops S.

The stops S, besides serving as solid stops for the sheet, serve as mounting blocks for floating contacts 49 which are insulated from the stops S by insulators 48 and a cover plate 51 of insulating material. The contact 49 is normally held spaced from a contactpla-te 47 by a pair of springs 50. Contact 49 is the actual electrical contact and.

projects in front of the stop block S as shown at X in FIG. 13 (approximately .005").

within .005 at one stop S after having engaged the other. stop S. Usually the sheet will hit one stop first, after contacting its contact 49 and depressing it the distance X. Then as soon :as the sheet hits the second contact .49 the circuit for the sensing device SD is completed and results in the entrance pinch rolls closing by the time the second contact 49 has been depressed and the sheet has contacted the second stop S, thus assuring a squared product within minutely accurate limits.

Before the sheet engages the stops, however, it engages bumpersfitl which are pivotally mounted at 81 on slides Each stop is an electrode insulated from the This .005" of travel. assures positioning of the leading edge of the sheet 108 to 'sponds to microcurrents in the wires 78 whenever a sheet 82 for vertical adjustment in response to double acting pneumatic cylinders C7 and C8 as will hereinafter appear. The slides 82 carry buffer cylinders 85 in which have pistons 84 on piston rods 86 that project from both ends of each cylinder. The bumpers 89 engage the upper ends of these rods while the lower. ends are adapted to be stopped by adjustable stops 88. The, cylinders 85 contain hydraulic fluid and have a closed hydraulic circuit so that.

the pistons 84 therein act as dash pots under control of flow-control needle valves 90 having adjusting knobs 92 to adjust the orifices and thereby the snubbing action on the bumpers 8t Adjustment of the valves 90 may be .having slots 62 through which the stops S and bumpers 80 extend on the ingoing side of the cutter'knives C1 and C2. This table. is suitably notched as. shown to accommodate the cutterknives, and on the outgoing side the table is slotted at 79 to receive an actuating finger 96 of a limit switch LS2 which has an actuating arm constrained to the vertical position shown. f

Referring to FIG. 12, a limit switch LS1 :is shown adapted to be actuated by astud 98 carried by the slide 82 which engages a roller'100 of the limit switch to actuate the switch when the slide moves downwardly a predetermined amount during the cycling of the apparatus.

1 Practical (operation 7 the rollinto suitable lengths and delivers them as sheets to our apparatus. Such a sheet 108 is illustrated being propelled by the conveyor 102- (on whichit rests by gravity) past the open pinch'rolls PR1 and PR2 and toward through the sheet betwen the two stops and through the wires 78 to actuate the sensingdevice .SD as indicated in FIG. 6. r

The amplifier A of the sensing device amplifies the microcurrent and sends current to a relay R1 and a time 'delay relay'TDRl; The relay R1 'actuates a solenoid valve SVl'to open communication from an air supply A to the top ofthe cylinders C3 andC4 thereby closing the pinch rolls PR1 and PR2 to firmly hold the sheet 108 properly oriented against the stops S. r

Soon after contact is made the. time delay. relayTDRl times out and actuates a solenoid valve SV2 as shown in FIG. 7 sending air to the tops of cylinders C7 and C8 to lower the stops S below the pass line of the sheet 108 so that it can progress past them. As soon as both stops S are lowered, their limit switches LS1 are closed to actuate the clutch CL (which heretofore has been declutched as shown by'dotted lines in FIGS. 5 and .6) to drive the chains 28 and 30 :and thereby the pinch rolls PR1, PR2, PR3 and PR4. The, pinch rolls PR1 and PR2 keep the sheet 108 oriented as they force'itpast the cutter knives C1 and C2 and the scraps indicated at -110 in FIG. '7

pass down a pair of chutes 112, shown in FIG. 10.

Alsoasin FIG. 7 the sheet 108'actuates the limit switch LS2 to its non-normal position, butthis limit switch is.

the type, that does not actuate a control 'circuituntil it returns to its initial position asshown in FIG. 8 after the sheet 198 has. passed, whereupon it actuates a time delay relay TDR2 as shown. a 7

Referring to FIG.=9 when the time delay relay TDR2 times outit ,actuates a reset relay RR which through a relay R2 actuateszthe solenoid valveSVl and through a relay R3 actuates the solenoid' valve SV2 for supplying air to the lower ends of thecylinders C3, C4, C7 and C8 thus opening the entrance pinch rolls PR1 and PR2.to permit a second sheet108a tosenter-our trimming apparatus, and raising the stops S to the initial position shown in FIG. 5. The relayRZ also actuates a solenoid valve SV3 which sends air to the lower ends of the'cylinders C5 and C6 for also opening the exit pinch rollsPR3 and PR4 whereupon the takeaway conveyor 106 removes the sheet 103 from our trimming apparatus, or if desired the sheets may be delivered to a stacker.

Still another function of the reset relay RR is to energize a time delay relay TDR3. Returning to FIG. 5 when the time delay relay TDR3 times out it actuates a relay R4 for again actuating the solenoid valve 8V3 for sending air to the upper ends of the cylinders C5 and C6 thus closing the exit pinch rolls PR3 and PR4 preparatory to receiving the sheet 108a after its side edges have been trimmed.

From the foregoing specification it will be obvious that we have provided a method for trimming the two side edges of a sheet parallel with each other and at right angles (or any other desired angle) relative to a leading edge of the sheet thus providing uniformly accurate sheets with respect to three of their edges whereupon the fourth edge may be trimmed at the desired angle relative to the parallel side edges thus producing truly rectangular sheets if desired or uniform sheets of other-than-rectangular outline.

The method steps disclosed may be varied to some extent, without departing from the real spirit and purpose of our invention. It is accordingly our intention to cover by our claims any equivalent method steps which may be reasonably included within their scope.

We claim as our invention:

1. A method for trimming the two opposite side edges of a sheet comprising the steps of cutting a desired length of sheet from a web of sheet, moving said length of sheet longitudinally by friction to engage its leading edge with a pair of stops spaced laterally of the sheet to angularly orient said leading edge, gripping the oriented sheet only after said leading edge has engaged both of said stops,

moving it as oriented longitudinally, and trimming the side edges thereof at predetermined angles relative to the oriented leading edge thereof.

2. A method for trimming the side edges of indivdual sheets comprising the steps of cutting desired lengths of sheet from a web of sheet, successively moving said lengths of sheet longitudinally to engage their leading edges with a pair of stops spaced laterally of the sheet to angularly orient said leading edges, gripping the oriented sheets only after their leading edges have engaged both of said stops, moving them as oriented longitudinally, trimming the side edges thereof at predetermined angles relative to the oriented leading edges thereof, and discharging the sheets after their side edges have been trimmed.

3. A method for trimming rectangular sheets comprising the steps of cutting a desired length of sheet from a web of sheet, moving said length of sheet longitudinally by friction to engage its leading edge with a pair of stops spaced laterally of the sheet to angularly orient said leading edge, gripping the oriented sheet only after said leading edge has engaged both of said stops, moving it as oriented longitudinally and trimming the side edges thereof parallel to each other and at right angles to the oriented leading edge thereof.

References Cited by the Examiner UNITED STATES PATENTS 4/28 Huston 83-35 7/39 Black 83-408 

1. A METHOD OF TRIMMING THE TWO OPPOSITE SIDE EDGES OF A SHEET COMPRISING THE STEPS OF CUTTING A DESIRED LENGTH OF SHEET FROM A WEB OF SHEET, MOVING SAID LENGTH OF SHEET LONGITUDINALLY BY FRICTION TO ENGAGE ITS LEADING EDGE WITH A PAIR OF STOPS SPACED LATERALLY OF THE SHEET TO ANGULARLY ORIENT SAID LEADING EDGE, GRIPPING THE ORIENTED SHEET ONLY AFTER SAID LEADING EDGE HAS ENGAGED BOTH OF SAID STOPS, MOVING IT AS ORIENTED LONGITUDINALLY, AND TRIMMING THE 